Vent-valve for train-stops.



VENT VALVE 'be APPLICATION HLEB r40v 22, IN2. xawm HAY P Mii.

HHIH

' train pipe,

`adapted to reciprocate in a entre HIRA'M G.' SEDGWICK, OF MILL VALLEY, CALIFORNIA, ASSIGNOR T0 TEE NATGNL SAFETY APPLIANCE COMPANY,

A CORPDRTION O? CALIFORNEA.

' VENT-VALVE :ion raam-sirens.

Specification of Letters Patent.

Application led November 22, 1912, Serial No. 732,986. Renewed May 27, i915. Serial No. 30,363.

T0 all whom t may concern:

Be it known that l, Hman G. SEDGWICK, a citizen of the United States, and a resident of Mill Valleypcounty of Marin, State of California, have invented certain new and useful Improvements in Vent-Valves for Train-Stops, of which the following is a full and clear specification, reference being had to the accompanying drawings, in which- Figure l is a side elevation of my improved valve apparatus; and Fig. 2 a longitudinal vertical section. thereof.

This invention has relation to that class of train stopping apparatus in which the brake pipe is vented by automatic-apparatus which is put int-o action by suitable.

means on the road bed as the train passes the road bed means; and the object of Athe present improvements is to provide a pneumatic venting mechanism which is capable of being started with but a very slight venting action and which when started will positively and gradually vent the brake pipe and thus apply the train brakes with a service stop.

A further object is to provide means whereby the engineers valve will be cut off from the train braking mechanism when the automatic venting mechanism is actuated so as to thereby take the control of the train entirely out of the hands of the engineer until after the automatic braking action is completed and the automatic devices are restored to normal position manually by the engineer, as more fully hereinafter set forth.

Referring to the drawing by referencecharacters, a. designates a vent pipe lwhich is provided at its end with a suitable valve b which is adapted to be opened by suitable means which coperate with a suitable road bed appliance. The devices l have illustrated are adapted to automatically vent the designated by the letter c, when said valve 7) is open, the devices being adapted to vent the brake pipe in such manner as to produce a service stop.

The vent valve'is shown as consisting of a hollow cylinder (i closed at its ends and cylinder e to which the brake pipe c is connected. A slot f in the valve al puts the interior of the valve d continuously in communication with the pipe c. The cylinder ci is provided with a longitudinal port g which is closed when the cylinder d is drawn back into the cylinder e, as shown in Fig. Q. To vent the brake pipe the cylinder' al is pushed endvvisely out of the cylinder e, so as to put the port g into communication with the atmosphere and gradually enlarge the port as the valve leaves the cylinder, thereby causing a gradual reduction of pressure in the brake pipe and bringing about a service stop of the train.

The vent valve d is connected by a rod it to a piston valve e', and this piston valve is 1n turn connected to a piston rod j, which latter extends into a cylinder fr and is attached to a piston Z working in said cylinder rThe valve Ai works in the cylinder m and ,is provided with a transverse passage a which communicates with opposite ports o in the cylinder m. One of these ports is connected to the engineers valve p and the other is connectedby a pipe g to the main reservoir 1' of the usual brake system. The

purpose of this valve z is to cut oft the sup, ply of the reservoir r to the engineersbvalveat the same time the valve d is operated to apply the brakes, thereby putting it out of the power of the engineer to remove the brakes until this apparatus is restored to normal condition..

A. piston rod s greater in cross sectional area than piston rod j is connected to the rear side of piston Z and extends out through a stuliing box in one head of the cylinder k. The piston rod j extends out through a stufng box in the other head. of this cyli,'inder k. The vent pipe a is connected by one branch t to the interior of cylinder it and by another branch u to the main reservoir r, a restoring valve 'v being located at the juncture of the pipes t and u with the pipe o. By reason of the dilerence in dialneter of the rods j and s the piston Z is exposed to different pressures on its opposite sides, an d the pipe t is connected to the cylinder at. the side of greater pressure while the pipe w coming from the main reservoir is connected to the interior of the cylinder at the other side of the piston, se that when both sides of the piston Z are exposed to main reservoir pressure the piston *will be moved toward and held the end. of the cylinder 'to which. pipe w is connected. Vihen the piston is in position e cylinder port 'w puts the spaces at bot of the piston into communication with each y other. A longitudinal port g/ in rod j is adapted when said rod y' is moved outward] y to put the interior of cylinder c into communication with the atmosphere through ,a port z in the adjacent cylinder head.

and open port y into port e, after which piston Z will continue to move in the same direction but at a much slower speed, this speedl depending on the area of port y. As this piston Z moves on this actuating stroke it will close valve z' and thus cutthe engneers valve oil' from the' air brake apparatus and will also move the valve fZ to venting position and thus apply the brakes of the train. To restore the parts to normal position (which position is shown in Fig. 2) it is simply necessary to admit reservoir pressure into the right hand end of cylinder lc, this being done by pulling open the small valve e, whereupon air from the main reser- .Voir will cause piston Z to move to the left hand end of the cylinder, after which the valve fv may be closed or allowed to close, since port a' has by that time restored communication between the two cylinder spaces to thus insure equal pressures of air in both ends of the cylinder. It will be observed that the port jl/ will not be closed until the piston Z is returned to its extreme. left hand position, but this will not prevent the piston being pushed back to that position against the reservoir pressure that is always on the left hand face of the piston since this port y is of a very small area as compared with the capacity of the supply pipe t.

It will be understood that while I prefer obtaining a lluid pressure necessary to operate thisvvalve apparatus from the main reservoir on the locomotive, it is .,within the spirit of my invention to use steam or other fluid for operating the valve mechan ism; and it will be understood also that it is within the spirit of my invention to use my valve apparatus with any brake setting means., the invention not being .confined to use with an air brake system. It will be understood also that it is within the spirit of this invention to vary the details of construction to a considerable extent.

I make no claim herein to anything covered by my copending application filed even date herewith and serially numbered 732,985.

Having thus described my invention,what I claim as new and desire to secure by Letters Patent, is-

1. In combination with a brake setting means, of means for operatingthe same by fluid pressure, consisting of a cylinder, a differential piston working therein and pro vided with a piston rod which is connected to said brake setting means, a Areservoir connected to the opposite ends of said cylinder so as to thereby normally hold the piston at one end of the cylinder, and means for venting the cylinder at the side of dominant pressure, whereby the differential pressure on the piston will be reversed and the piston will be thereby caused to move toward the other end of the cylinder, said venting means consisting of means for preliminarily venting the cylinder to obtain a quick action of the piston and for thereafter slowly venting the cylinder, for the purpose set y forth.

2. In combination with a brake setting means, of means for operating the same by fluid pressure, consisting of a cylinder, a differential piston working therein and provided with a piston rod which is connected to said brake setting' means, a reservoir con-- nected to the opposite ends of said cylinder so as to thereby normally hold the piston at one end of the cylinder, and means for venting'the cylinder at the side of dominant pressure, whereby the dii'erential pressure on the piston will be reversed and the piston will be thereby caused to move toward the other end of the cylinder, said venting means consisting of means for preliminarily venting the cylinder to obtain a quick action of the piston and 'for thereafter slowly venting the cylinder, means being provided for cutting ott the reservoir pressure from the venting side of the piston by said preliminary quick action of the piston.

In testimony ,whereof I hereunto aiiix my signature in `the presence of two witnesses.

HIRAM o. sEDewroK. 

